This proposal builds upon a five year research project, SEARCHfor Diabetes in Youth, its standardized data collection effort, experienced investigator team, established case ascertainment infrastructure, and ethnically diverse population base. This is a common, integrated application from the six SEARCH clinical sites, which Droposes to continue and expand the work performed by SEARCH in order to address the following specific research aims: AIM 1: Prospectively ascertain newly diagnosed (2006-2009) incident cases age less than 20 years in order to estimate temporal trends in incidence of DM in youth; AIM 2: Conduct longitudinal follow-up of incident cases already recruited to SEARCH in 2002-2005 in order to document the evolution of newly diagnosed DM accordingto clinical and biochemical factors; AIM 3: Complete analyses initiated in the first five years of SEARCHand expand the scope of quality of care assessment to encompass more broadly defined concepts and measures of quality; AIM 4: Develop and validate simple and low-cost case definitions and classifications of DM types in youth that can be used for public health surveillance. The novelty of this proposal includes its comprehensive nature that brings together major and timely facets of childhood DM research: an epidemiologic study, unique in the United States, of temporal trends in the incidence of DM in youth; a pathophysiologic component addressing the natural history of DM in youth; a study of processes of care and quality of life; and a public health perspective on case classification of DM in youth. This research is critically important to public health as it will provide information about whether and how much DM is increasing among youth of different racial/ ethnic groups in the United States, about how DM impacts on the physical health, including complications, as well as valuable data regarding the quality of care and the quality of life of these youth. The particular strengths of the South Carolina clinical site include: 1) extensive experience of the investigators in national scientific leadership including leadership in SEARCH publications and SEARCH ancillary studies; 2) a highly stable and experienced local SEARCH clinic staff to ensure efficient operation of the SEARCH project; and 3) success in identification and inclusion of African American youth, including many living in medically underserved communities.